A Wide Air Gap Flux Switching Bearingless Motor with Odd and Even Pole Pair Numbers

This paper introduces a bearingless motor topology with a magnet-free rotor that provides a higher rotor torque density and wider magnetic air gap compared to previously published topologies. The stray flux is minimized by using a stator with only eight teeth in temple configuration that contain permanent magnets. The motor performance is analyzed based on experimental prototypes, that were designed using 3D FEM simulations, for even and odd rotor pole pair numbers of six and nine, respectively. Control schemes that compensate parasitic radial forces to achieve stable magnetic levitation of the rotors are presented. The implemented prototypes reached a rotational speed of 2000 rpm and a maximum torque of 8 Nm.